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Glacial geologic studies in the Southern Hemisphere (SH) mid-latitudes (40-54°S) indicate renewed glacial activity in southern South America (Patagonia) and New Zealand's (NZ) South Island starting at ∼7 kyr, the so-called neoglaciation. Available data indicate that neoglacial advances in these regions occurred during a rising trend in atmospheric CO and CH concentrations, lower-than-present but increasing summer insolation and seasonality contrasts. In this paper we examine the climatological context in which neoglaciations occurred through analysis of the complete Paleoclimate Modelling Inter-comparison Project (PMIP2) database of simulations at 6 kyr for the SH. We observe that the amplitude of the annual insolation cycle in the SH did not change significantly at 6 kyr compared to the pre-industrial values, the largest difference occurring in autumn (MAM, negative anomalies) and spring (SON, positive anomalies). The simulated changes in temperatures over the SH respond to the insolation changes, with a 1-2 month delay over the oceans. This results in a reduced amplitude of the annual cycle of temperature and precipitation over most continental regions, except over Patagonia and NZ, that show a slight increase. In contrast, large-scale circulation features, such as the low and upper level winds and the subtropical anticyclones show an amplified annual cycle, as a direct response to the increased/decreased insolation during the transitional seasons SON/MAM. In the annual mean, there is a small but consistent equatorward shift of the latitude of maximum wind speed of 1-3° over the entire SH, which results in a small increase of wind speed over the South Pacific and Atlantic Oceans north of ∼50°S and a widespread decline south of 50°S. PMIP2 simulations for 6 kyr, indicate that in the annual mean, the SH mid-latitudes were colder, wetter and with stronger winds north of about 50°S. These conditions are consistent with the observed neoglacial advances in the region, as well as with terrestrial paleoclimate records from Patagonia that indicate cooling and a multi-millennial rising trend in Southern Westerly Wind intensity starting at ∼7.8 kyr. [ABSTRACT FROM AUTHOR]

We present a general bathymetric map of Lago Fagnano, the largest ice-free lake of the Southern Hemisphere, located in the central part of the Tierra del Fuego Island. The map has been obtained compiling all the available bathymetric soundings and depth-converted high-resolution seismic profiles, collected in the course of several geophysical campaigns. The lake occupies a 110-km long, E-W trending tectonic depression within the southernmost tip of the Andean Cordillera, where the South America-Scotia plate boundary traverses the Tierra del Fuego Island. The map allows us to identify the main morpho-bathymetric features of Lago Fagnano. The lake floor is divided into two principal sectors of different water depths, separated by a main shoal located in the central part of the lake. Maximum water depth (206 m) is found in the eastern part, whereas water depths in the western half do not exceed 165 m. In this paper, we describe the geometry and the general morphological characteristics of the basin, which was generated by a combination of distinct tectonic processes, and later superposed by Late Quaternary glacial and glacio-lacustrine dynamic events. [ABSTRACT FROM AUTHOR]